Automatic generation of test drivers

ABSTRACT

A test driver generator is provided for generating test drivers. The test driver generator receives test expressions designating execution sequences of test functions of software interfaces and corresponding attribute value specifications for the designated test functions&#39; parameter attributes. Each test expression designating a number of test functions to be executed in a certain sequence, and each corresponding attribute value specification specifies selected attribute values of the test functions&#39; parameter attributes. For each test expression and corresponding attribute value specifications of a software interface, the test driver generator, in response, generates a test driver that can execute the specified test functions in the designated order with all combinations of the selected attribute values of the test functions&#39; parameter attributes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of software testing. More specifically, the present invention relates to automatic generation of test drivers for executing test functions in sequence.

2. Art Background

Traditionally, software testing was done on an ad-hoc basis. As the complexity of software increases with increasing function being offered, various approaches, techniques and tools have been developed to provide a more structured or disciplined approach to software testing. From a process perspective, typically a phase approach is used to divide software testing into different stages, such as requirement testing, design testing, unit testing, function testing, and system testing. For each stage, different testing techniques, such as boundary value testing and sampling, are applied to improve test coverages. Additionally, various testing tools, such as test case generators and simulators, are developed to improve testing efficiency.

Traditionally, software specification and design were also done on an informal basis. Similarly, as the complexity of software increases with increasing function being offered, various techniques and tools have been developed to provide a more formal approach to software specification and design. Particular examples of formal design techniques include top down design and data flow analysis. Particular examples of formal design tools include formal specification and design languages and various Computer Aided Software Engineering (CASE) tools.

The advent of formal specification and design languages offers a new opportunity for further imposing structure and discipline on software testing. The formal specifications can be submitted to machine based analysis. If the proper behavior of a software interface can be adequately described by its formal specification, then testing functions can be automatically and systematically generated for the software interface from the formal specification. Furthermore, the generated testing functions can be auto-checking. An auto-checking test function is a function that can invoke and execute a procedure to be tested and knows enough about the procedure to be able to determine whether the procedure behaved properly or improperly when the procedure was tested. A particular example of such an auto-checking testing function generator is disclosed in U.S. Pat. No. 5,357,452.

Typically, each auto-checking testing function requires a number of parameters to be provided as inputs. Each parameter may have one or more attributes, and each attribute may take on one of a number of discrete values or any value over a range. Thus, even for a small number of parameters and attributes, the potential combinations of input values are enormously large, and, for all practical purposes, approach infinity.

Therefore, it is desirable to be able to provide a test driver for a software interface that can execute a collection of auto-checking test functions selectively to test the software interface. It is further desirable if the auto-checking test functions can be executed selectively for selected combinations of the attribute values of the auto-checking test functions' parameter attributes. It is further desirable to have such a test driver automatically generated from a specification designating the auto-checking test functions of the software interface and specifying selected attribute values of the test functions' parameter attributes. A particular example of such a test driver generator is disclosed in U.S. Pat. No. 5,359,546.

Additionally, it is further desirable to be able to designate the test functions to be tested as a sequence of interrelated test functions. In other words, the values produced by one function to be used by another function. As will be disclosed, the present invention provides methods and apparatus for designating sequences of interrelated test functions of software interfaces and specifying selected attribute values of the test functions' parameter attributes, and automatically generating from these designations/specifications, test drivers for executing the designated test functions in sequence with all combinations of the selected attribute values, thereby achieving the desired results described above.

SUMMARY OF THE INVENTION

Methods and apparatus for designating sequences of interrelated test functions of software interfaces and specifying selected attribute values of the test functions' parameter attributes, and automatically generating from these designations/specifications, test drivers for executing the designated test functions in sequence with all combinations of the selected attribute values are disclosed. The methods and apparatus have particular application to automated software testing, in particular, software interfaces having a number of procedures and corresponding auto-checking test functions that are interrelated. The procedures and the auto-checking test functions may be implemented in any of the well known programming languages, such as C, employing any of the well known programming methodologies, such as objected oriented programming.

A test driver generator is provided for generating test drivers. The test driver generator receives test expressions designating execution sequence of test functions of software interfaces and corresponding attribute value specifications for the designated test functions' parameter attributes. Each test expression designates a number of test functions to be executed in a certain sequence, and each corresponding attribute value specification specifies selected attribute values of the test functions' parameter attributes. For each test expression and corresponding attribute value specifications of a software interface, the test driver generator, in response, generates a test driver that can execute the specified test functions in the designated order with all combinations of the selected attribute values of the test functions' parameter attributes.

In the presently preferred embodiment, the test function sequences and the corresponding selected attribute values are designated/specified in a combined test function sequence and attribute value designation/specification. The test functions are auto-checking. For some embodiments, depending on the programming languages used for the test functions and the programming methodologies employed for the software interfaces, the test function sequence designations, and the corresponding selected attribute value specifications are augmented by supplemental test function and/or object type and method definitions.

In one embodiment, the test driver generator comprises a parser, an intermediate representation builder, and a code generator. The parser receives the test function sequence designations and the corresponding selected attribute value specifications as inputs, and tokenizes the test function sequence designations and the attribute value specifications. The intermediate representation builder receives the tokenized test function sequence designations and the tokenized attribute value specifications as inputs, and generates intermediate representations for these designations/specifications. The code generator receives the intermediate representations as inputs, and generates test drivers for executing the designated test functions in sequence with all combinations of the selected attribute values of the test functions' parameter attributes.

Furthermore, in this embodiment, the parser parses and tokenizes the test function designations and the attribute value specifications based on formal grammar. The intermediate representation builder builds a syntax tree. The code generator generates the test drivers using the syntax tree.

Each test driver is generated with the same execution flow for executing a number of test functions in sequence, with all combinations of the selected attribute values of the test functions' parameter attributes. For each sequence of test functions, the corresponding test driver creates the combinations of the selected attribute values of the selected test function's parameters one at a time. For each combination of the selected attribute values, the test driver either creates actual test data in line or calls corresponding user supplied test data creation functions to create the actual test data. Next, the corresponding test driver creates the local test variables and evaluate test expressions required for executing the designated test functions in sequence. Then the corresponding test driver invokes the designated test functions in sequence, and accumulates testing statistics based on results returned from the invoked test functions. After accumulating the statistics, the corresponding test driver deletes all test data created for the particular combination of attribute values, calling user supplied test data deleting functions if necessary. The process is repeated for each combination of the selected attribute values of each sequence of test functions.

For some embodiments, depending on the programming languages used for the test drivers, the test drivers are generated with complementary test include files and/or test driver functions. The complementary test driver include files comprise selected attribute value definitions for the designated test functions' parameter attributes, and user supplied test data creation and deletion function definitions. The complementary test driver functions are invoked by the test drivers during execution to generate attribute values to create a particular combination of attribute values for a test function's parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features, and advantages of the present invention will be apparent from the following detailed description of the preferred and alternate embodiments of the present invention with references to the drawings in which:

FIG. 1 shows a functional block diagram illustrating the hardware elements of an exemplary computer system that incorporates the teachings of the present invention.

FIG. 2 shows a functional block diagram illustrating the software elements of the exemplary computer system of FIG. 1.

FIG. 3 shows a functional block diagram illustrating the input and output of the test driver generator of the present invention.

FIGS. 4a-4c illustrate the presently preferred embodiment of the combined test function sequence and attribute value designation/specification, the supplemental test function definitions and the supplemental object type and method definitions of the present invention for a software interface.

FIGS. 5a-5c show an exemplary combined test function sequence and attribute value designation/specification, an exemplary collection of supplemental test function definitions and an exemplary collection of supplemental object type and method definitions of the present invention for an exemplary software interface.

FIG. 6 shows a function block diagram illustrating one embodiment of the test driver generator of the present invention.

FIG. 7 illustrate the execution flow of each generated test driver of the present invention.

FIGS. 8a-8c show an exemplary generated test driver of the present invention.

FIGS. 9a-9b shows an exemplary generated test driver include file of the present invention.

FIGS. 10a-10c show an exemplary collection of generated test driver functions of the present invention.

FIGS. 11a-11b show three pairs of exemplary user supplied test data creation and deletion functions.

DETAILED DESCRIPTION

Methods and apparatus for designated sequences of interrelated test functions of software interfaces, and specifying selected attribute values for the test functions' parameter attributes, and automatically generating from these designations/specifications test drivers for executing the test functions in sequence with all combinations of the selected attribute values are disclosed. The methods and apparatus have particular application to automated software testing, in particular, software interfaces having a number of procedures and corresponding test functions, including auto-checking test functions. The procedures and corresponding test functions may be implemented in any of the well known programming languages, such as C, employing any of the well known programming methodologies, such as objected oriented programming. In the following description for purposes of explanation, specific numbers, materials and configurations are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without the specific details. In other instances, well known systems are shown in diagrammatical or block diagram form in order not to obscure the present invention unnecessarily. Additionally, while the present invention will be described with auto-checking test functions, based on the descriptions to follow, it will be appreciated that the present invention may be practiced with test functions that are not auto-checking.

Referring now to FIG. 1, a functional block diagram illustrating an exemplary computer system that incorporates the teachings of the present invention is shown. Shown is a computer 10 comprising a central processing unit (CPU) 12, a memory 14, and an I/O module 16. Additionally, the computer system 10 also comprises an input device 18, an output device 20 and a storage device 22. The CPU 12 is coupled to the memory 14 and the I/O module 16. The input device 18, the output device 20, and the storage device 22 are also coupled to the I/0 module 16. The I/O module 16 in turn is coupled to a network.

Except for the manner they are used to practice the present invention, the CPU 12, the memory 14, the I/O module 16, the input device 18, the output device 20, and the storage device 22, are intended to represent a broad category of these elements found in most computer systems. Their constitutions and basic functions are well known and will not be further described here.

Referring now to FIG. 2, a functional block diagram illustrating the software elements of the computer system of FIG. 1 is shown. Shown is an operating system 32 comprising a file subsystem 34 and a process control subsystem 36. The file subsystem 34 is responsible for managing files, allocating file spaces, administering free space, controlling access to files and retrieving data from files. The process control subsystem 36 is responsible for process synchronization, interprocess communication, memory management and process scheduling. The file subsystem 34 and the process control subsystem 36 are intended to represent a broad category of these elements found in most operating systems. Their constitutions and functions are well known and will not be further described here.

The software elements 30 further comprise programming language compilers, software tools/utilities and their runtime libraries 38, the test driver generator of the present invention 40, and the generated test drivers of the present invention 42. The programming language compilers, software tools/utilities and their runtime libraries 38 are used to develop and execute application programs, in particular, the test driver generator 40 and the generated test drivers 42 of the present invention. The language compilers, runtime libraries, tools/utilities 38 are intended to represent a broad category of these software elements found in most computer systems. Their constitutions and functions are well known, and will not be further described here. The test driver generator and the generated test drivers of the present invention will be described in further detail below with references to FIGS. 3, 6, 7, and 8a-8c.

While for ease of understanding, the present invention is being illustrated with embodiments of the test driver generator that are implemented in high-level programming languages, and test drivers that are generated in high-level programming languages, it will be appreciated, based on the descriptions to follow, that the present invention may be practiced with the test driver generator and the test drivers implemented/generated in a variety of programming languages.

Referring now to FIG. 3, a functional block diagram illustrating the input and output of the test driver generator of the present invention is shown. Shown is the test driver generator 40 receiving a number of test function sequence designations of software interfaces, and corresponding selected attribute value specifications 44 for the test functions' parameter attributes as inputs. In the present preferred embodiment, the test function sequence designations and the corresponding selected attribute value specifications for a software interface are made in a combined test function sequence and attribute value designation/specification. For some embodiments, the test function sequence designations and attribute value specifications are augmented with supplemental test function definitions 46, and/or object type and method definitions 48. It will be appreciated that the test function sequence designations, the attribute value specifications, the supplemental test function definitions 46, and the object type and method definitions 48 may be provided to the test driver generator 40 in a variety of manners. For examples, the designations, specifications and supplemental definitions may be provided through an input device or pre-stored in a storage device accessible to the test driver generator 40. The test function sequence designations and attribute value specifications 44, the supplemental test function definitions 46 and the supplemental object type and method definitions 48 will be described in further detail with references to FIGS. 4a-4c, and 5a-5c.

Continue to refer to FIG. 3, for each collection of test function sequence designations and attribute value specifications 44 of a software interface, the test driver generator 40 generates a test driver 42 for executing the designated auto-checking test functions in sequence with all combinations of the selected attribute values. For some embodiments, depending on the programming languages used for the test drivers and the programming methodologies employed, the test drivers 42 are generated with complementary test driver include files 50 and complementary test driver functions 52. The complementary test driver include files 50 are included during compilation of the test drivers 42. The complementary test driver functions 50 are invoked by the test drivers 42 during execution. The test driver generator 40 will be described in further detail with references to FIG. 6. The test drivers 42, the test driver include files 50, and the test driver functions 52 will be described in further detail with references to FIGS. 7, 8a-8c, 9 and 10.

Referring now to FIGS. 4a-4c, three diagrams illustrating the presently preferred combined test function sequence and attribute value designation/specification, the supplemental test function definitions, and the supplemental object type and method definitions of the present invention are shown. FIG. 4a illustrates the combined test function sequence and attribute value designation/specification, while FIGS. 4b and 4c illustrate the supplemental test function definitions, and the supplemental object type and method definitions respectively.

Shown in FIG. 4a is a combined test function sequence and attribute value designation/specification 44 comprising an interface identification 51, a test specification 54, and a number of attribute value specifications 56 for test function parameters. Test specification 54 specifies in expression form a sequence of interrelated test functions corresponding to procedures of a software interface, including their parameters, via one or more sub-expressions 53b and/or local variables 53a. In the "degenerate case", a test function sequence designation may be a single test function specification as in the prior art. Each attribute value specification, e.g. 57, specifies the selected attribute values for all attributes of a test function parameter. Additionally, the attribute value specifications 56 may support global declaration of attributes and their selected attributes values, thus allowing the globally declared attributes and their selected attribute values to be shared among test function parameters.

Shown in FIG. 4b is a collection of supplemental test function definitions 46 comprising a number of test function definitions, e.g. 58. Each supplemental test function definition, e.g. 58, defines an auto-checking test function and its parameters. A particular example of supplemental test function definition collection is the auto-checking test function include file generated by the auto-checking test function generator described in U.S. Pat. No. 5,357,452.

Shown in FIG. 4c is a collection of supplemental object type and method definitions 48 comprising a number of object type definitions 60, a number of inheritance definitions 62, and a number of method definitions 64. Each object type definition, e.g. 59 defines an object type of an object oriented software interface. Each inheritance definition, e.g. 61, defines an inheritance characteristic for an object class and its super class. Each method definitions, e.g. 63, defines a method of an object orient software interface. A particular example of supplemental object type and method definition collection is the object type and method definition file generated by the auto-checking test function generator described in U.S. Pat. No. 5,357,452.

Except for the basic requirements described above, the auto-checking test functions of a software interface, and the corresponding selected attribute values of the test functions' parameter attributes may otherwise be specified in a variety of manners. For further descriptions of auto-checking test function include files, and object type and method definition files generated by an automatic auto-checking test function generator, see U.S. Pat. No. 5,357,452.

Referring now to FIGS. 5a-5c, three diagrams showing an exemplary combined test function sequence and attribute value designation/specification, an exemplary collection of supplemental test function definitions, and an exemplary collection of supplemental object type and method definitions are shown. FIG. 5a shows the exemplary combined test function sequence and attribute value designation/specification, while FIGS. 5b and 5c show the exemplary collection of supplemental test function definitions and the exemplary supplemental object type and method definitions respectively.

Shown in FIG. 5a is an exemplary combined test function sequence and attribute value designation/specification 44' for an object oriented interface "am" comprising an exemplary test function sequence designation 53' having a sequence of three exemplary interrelated test functions, 53a'-53c', designating three exemplary auto-checking test functions, "bank.create₋₋ account", "acct.withdraw", and "acct.deposit", their parameters, and local variable "acct" in C like syntax.

Additionally, the exemplary combined test function sequence and attribute value designation/specification 44' comprises three exemplary attribute value specifications, 55a'-55c', specifying exemplary attribute values for an exemplary attribute "attrsz" for exemplary test function parameters "amt" and "offset" and exemplary attribute values for an exemplary attribute "type" for an exemplary test function parameter "bank". The exemplary attribute values for the exemplary attribute "type" 55c' are explicitly specified, i.e. "commerce, snal, consumer, cu". The exemplary attribute values for the exemplary attribute "attrsz" 55a' and 55b' are implicitly specified through an exemplary globally declared attribute value "size", i.e. "negative, zero, small, large" 57'.

Note that "acct" is a local variable, created by invocation of the method "bank.create₋₋ account", and that "offset" is a parameter to the test sequence. Further note that the argument to the method "acct.withdraw" is constructed by an arithmetic operation combining two parameter variables "amt" and "offset"to create a new value.

Shown in FIG. 5b is the exemplary supplemental collection of test function definitions "am₋₋ test.h" 46', comprising four exemplary test function definitions 58' for four exemplary auto-checking test functions, "test₋₋ am₋₋ create₋₋ account", "test₋₋ account₋₋ deposit", "test₋₋ account₋₋ withdraw", and "test₋₋ account₋₋ get₋₋ balance". For each exemplary auto-checking test function, the corresponding exemplary test function definition specifies its parameters.

Shown in FIG. 5c is an exemplary collection of object type and method definitions 48' comprising three exemplary object type definitions 60', one exemplary inheritance definition 62', and four exemplary method definitions 64'. The exemplary method definition "am.create₋₋ account" resolves the method "bank.create₋₋ account" (bank=am) to the exemplary auto-checking test function "test₋₋ am₋₋ create₋₋ account" whose parameters are to be resolved in the exemplary supplemental collection of test function definitions "am₋₋ test.h". Similarly, the exemplary method definition "account.deposit" resolves the method "acct.deposit" (acct=account) to the exemplary auto-checking test function "test₋₋ am₋₋ account₋₋ deposit" whose parameters are also to be resolved in the exemplary supplemental collection of test function definitions "am₋₋ test.h". Likewise, the exemplary method definition "account.withdraw" resolves the method "acct.withdraw" (acct=account) to the exemplary auto-checking test function "test₋₋ am₋₋ account₋₋ withdraw" whose parameters are to be resolved in the exemplary supplemental collection of test function definitions "am₋₋ test.h".

Referring now to FIG. 6, a functional block diagram illustrating one embodiment of the test driver generator of the present invention of the present invention is shown. Shown is the test driver generator 40 comprising a parser 66, an intermediate representation builder 68, and a code generator 70. These elements are sequentially coupled to each other. Together, they generate the test drivers, the parameter/attribute functions and the test driver include files of the present invention in C and C like syntaxes respectively for object oriented software interfaces whose auto-checking test functions are implemented in a programming language that supports inter-program call from a C program, in response to received test and parameter/attribute specifications using C like syntaxes.

The parser 66, the intermediate representation builder 68, and the code generator 70, are implemented in like manners similar to a broad category of equivalent elements found in many well known programming language compilers. Their constitutions, basic functions offered, and operation flows will only be briefly described here.

The parser 66 receives the test function designations and the attribute values specifications, including supplemental test function definitions, and/or supplemental object type and method definitions as inputs, and tokenizes the various designations, specifications and definitions. The intermediate representation builder 68 receives the tokenized designations, specifications, and definitions as inputs, and generates intermediate representations for these designations, specifications, and definitions. The code generator 70 receives the intermediate representations as inputs, and generates executable code for the test drivers and the test driver functions. Additionally, the code generator 70 also generates the test driver include files.

In this particular embodiment, the parser 66 parses and tokenizes the expressions based on formal grammar. The intermediate representation builder 68 builds a syntax tree. The code generator 70 generates the executable code for the test drivers and the test driver functions, and the test driver include files using the syntax tree.

For further descriptions on various parsers, intermediate representation builders, code generators, and syntax trees, and closures, see A. V. Aho, R. Sethi, and J. D. Ullman, Compilers Principles, Techniques and Tools, Addison-Wesley, 1986, pp. 25-388, and 463-512.

It will be appreciated that the test driver generator of the present invention may be practiced with other embodiments having elements providing equivalent functions provided by the elements of the above embodiment. It will further be appreciated that these other embodiments may generate test drivers and test driver functions in programming languages other than C, related outputs in syntaxes other than being C like, in response to test function designations, attribute value specifications, and supplemental definitions, in syntaxes also other than being C like, and/or for software interfaces that are non-object oriented.

Referring now to FIG. 7, a block diagram illustrating the execution flow of each generated test driver is shown. Each generated test driver has the same execution flow 72. Initially, the test driver creates a combination of attribute values for the test function parameters, block 73. As described earlier, for some embodiments, the test driver calls the test driver functions to generate the attribute values for creating the particular combination.

Then, the test driver creates the test data for the particular combination of attribute values, block 74. The test driver either creates the test data in line and/or calls user supplied test data creation functions to create the test data. After creating the test data, the test driver initializes the local variables and evaluates test expressions required for executing the auto-checking test functions in sequence, step 75, unless the sequence has no local variables nor test expressions, such as the degenerated case of a sequence of one auto-checking test function. For such sequences, the test driver proceeds directly to step 76. If the test expressions include sub-expressions, the sub-expressions are evaluated in order. At step 76, the test driver invokes the auto-checking test function, block 76. Upon returning from the auto-checking test function, the test driver updates the local variables and accumulates test statistics based on the results returned from the auto-checking test function, block 78. After updating the local variables and accumulating test statistics, the test driver repeats steps 76 and 78 again, until all auto-checking test functions of the sequence have been executed in accordance with the designated order. Then, the test driver discards the test data created for the particular combination of attribute values, block 82, calling user supplied test data deletion functions if necessary.

Blocks 74-82 are repeated until they have been performed for each combination of the selected attribute values specified in the attribute value specifications. The user supplied test data creation and deletion functions will be described in further detail later with references to FIGS. 11a-11b.

Referring now to FIGS. 8a-8c, three diagrams showing an exemplary generated test driver of the present invention are shown. Shown in FIGS. 8a-8c is the exemplary test driver generated for the exemplary test function sequence and attribute value designation/specification and supplemental definitions of FIGS. 5a-5c, having an execution flow as described earlier.

Initially, the exemplary test driver initializes a number of control variables, e.g. "totct". The exemplary test driver then uses a number of control variables, i.e. "I0", "i1" and "i2", to loop through execution of the interrelated test functions in accordance with the designated order. At each pass, the exemplary test driver sets up the test variables 86, e.g. "amount am=tv₋₋ amt.provide(i0)", then executes the interrelated test functions 88, i.e. "account acct=acf₋₋ create₋₋ account(bank, amt); acf₋₋ withdraw (acct, amt+offset); acf₋₋ deposit (acct, amt)". As described earlier, upon executing the test functions for one combination of attribute values, the test driver tears down the test data (including the test variables) 90, e.g. "tv₋₋ bank.relinquish (bank, i2)". The remaining source statements illustrated in FIG. 8b and 8c are for exception handling.

Referring now to FIGS. 9a-9b, a diagram showing an exemplary generated test driver include file is shown. The test driver include files are used to define other common include files, the attribute values specified, and the user supplied test data creation and deletion functions for the generated test drivers.

As shown in FIGS. 9a-9b, the exemplary test driver include file 102 generated in conjunction with the test driver for the exemplary test function sequence and attribute value designation/specification and the supplemental definitions of FIGS. 5a-5c comprises four exemplary attribute value definitions, 104a-104d, one for each set of the exemplary attribute values specified, "size", "acct₋₋ bal", "acct₋₋ typ", and "bank₋₋ type", and three exemplary pairs of user supplied test data creation and deletion functions, "provide₋₋ acct" and "relinquish₋₋ acct", "provide₋₋ amt" and "relinquish amt", and "provide₋₋ bank" and "relinquish₋₋ bank", 106a-106c.

Referring now to FIGS. 10a-10c, two diagrams showing an exemplary collection of generated test driver functions are shown. The generated test driver functions are invoked by the test driver during its execution for construction of a particular combination of attribute values for the test function's parameters. The generated test driver functions comprise a test driver function for each of the attributes specified in the test function and attribute value designation/specification. Each generated test driver function receives an index value as input. In response, the generated test driver function returns an attribute value specified in the test function and attribute value designation/specification.

As shown in FIGS. 10a-10c, the exemplary test driver functions generated for the exemplary test function and attribute value designation/specification and the supplemental definitions of FIG. 5a-5c, comprise four exemplary test driver functions, "size", "acct₋₋ bal", "acct₋₋ typ", and "bank₋₋ type", 110-116, one for each of the four exemplary attributes "sz", "bal", "typ" and "type". In response to an input value, each of the four exemplary test driver functions, 110, 112, 114 or 116, returns a corresponding exemplary attribute value specified, i.e. "negative", "zero", "small" or "large" for the exemplary attribute "size", 110, "neg", "zero", "tiny", "huge" or "enorm" for the exemplary attribute "acct₋₋ bal", 112, "economy", "standard", or "gold" for the exemplary attribute "typ" 114, and "commerce", "sni", "consumer" or "cu" for the exemplary attribute "type" 116.

Referring now to FIGS. 11a-11b, two diagrams showing three exemplary pairs of user supplied test data creation and deletion functions of the present invention are shown. Each test data creation function creates the actual test data for a particular combination of attribute values of the test function's parameters. Each test data creation function receives the applicable attribute value for the particular combination as inputs. In response, the test data creation function creates the actual test data. Similarly each test data deletion function deletes the actual test data created for a particular combination of attribute values. Each test data deletion function receives the applicable attribute values for the particular combination as inputs. In response, the test data deletion function deletes the actual test data previously created.

As shown in FIGS. 11a-11b, the exemplary collection of test data creation and deletion functions, 120a and 120b, comprises three exemplary pairs of test data creation and deletion functions, "provide₋₋ acct" and "relinquish₋₋ acct", 122a and 124a, "provide₋₋ amt" and "relinquish₋₋ amt", 122b and 124b, and "provide₋₋ bank" and "relinquish₋₋ bank", 122c and 124c. The "provide₋₋ acct" and "relinquish₋₋ acct" functions, 122a and 124a, create and delete an "account" object of a particular "account balance". The "provide₋₋ amt" and "relinquish₋₋ amt", 122b and 124b, create and delete an "amount" object of a particular "amount size". The "provide₋₋ bank" and "relinquish bank" functions, 122c and 124c, create and delete a "bank" object of a particular "bank type".

While the present invention has been described in terms of presently preferred and alternate embodiments, those skilled in the art will recognize that the invention is not limited to the embodiments described. The methods and apparatus of the present invention can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting on the present invention. 

What is claimed is:
 1. In a computer system comprising a software interface having a plurality of procedures and corresponding test functions for testing said procedures, a method for automatically generating a test driver for executing said test functions in sequence, said method comprising the steps of:a) declaring at least one local variable to be used by said test functions for testing said plurality of procedures, wherein said at least one local variable is modified by a first test function in said plurality of functions and said modified local variable is used by a second test function in said plurality of functions, and expressing formally sequential execution order of said test functions using said at least one local variable; b) specifying assignable attribute values selected for each of said test function parameter attributes, said test functions comprising a plurality of parameters having a plurality of attributes, said attributes being assigned attribute values when said test functions are invoked; and c) generating said test driver based on said local variable declaration and said formally expressed sequential execution order of said test functions and said specified assignable attribute values, said generated test driver when invoked executes said test functions in said designated order with all combinations of said specified assignable attribute values.
 2. The method as set forth in claim 1, wherein, said test functions are auto-checking test functions.
 3. The method as set forth in claim 1, wherein, said formally expressed test function execution order and said specified attribute value specifications are augmented by local test variable declarations and supplemental test function definitions.
 4. The method as set forth in claim 1, wherein, said software interface is object oriented, said formally expressed test function execution order and said specified attribute value specifications are augmented by supplemental object type and method definitions.
 5. The method as set forth in claim 1, wherein, said step c) comprises generating an include file for said generated test driver, said include file comprising attribute definitions and user supplied test data creation and deletion function definitions, said include file being included at compilation of said generated test driver.
 6. The method as set forth in claim 1, wherein, said step c) comprises generating test driver functions for said generated test driver, said test driver functions being called by said generated test driver during its execution to provide said generated test driver with a particular combination of said attribute values.
 7. The method as set forth in claim 1, wherein, said step c) comprises the steps of:c.1) parsing and tokenizing said formally expressed test function execution order and said specified attribute value specifications based on a formal grammar; c.2) generating intermediate representations for said formally expressed test function execution order and said specified attribute value specifications, said intermediate representation being a syntax tree; and c.3) generating executable code for said test driver using said generated intermediate representations.
 8. In a computer system comprising a software interface having a plurality of procedures and corresponding test functions for testing said procedures, wherein said test functions comprising a plurality parameters having a plurality of attributes, said attributes being assigned attribute values when said test functions are invoked, a method for sequentially executing said test functions in order with pre-selected combinations of said attribute values, said method comprising the steps of:a) creating one of said pre-selected combinations of said attribute values for said test functions; b) creating test data for said created one of said pre-selected combinations of said attribute values; c) evaluating a test expression expressing execution order of said test functions to determine next test functions to be executed; d) executing said next test functions using said created test data; e) repeating said steps c) through d) to execute said test functions in accordance with the execution order expressed by said test expression; f) deleting said test data created for said created one of said pre-selected combinations of said attribute values; and g) repeating said steps a) through f) for each of pre-selected combinations of said attribute values.
 9. The method as set forth in claim 8, wherein,said test functions are auto-checking test functions; and said step d) further comprises accumulating execution statistics for said test functions after executing each of said test functions.
 10. The method as set forth in claim 8, wherein, said created one of said pre-selected combinations of said attribute values is created in said step c) by calling test driver functions to provide an assignable attribute value for each of said attributes of said chosen test function's parameters.
 11. The method as set forth in claim 8, wherein, said test data is created and deleted in said steps b) and f) by calling a user supplied test data creation and a user supplied test data deletion function respectively.
 12. In a computer system comprising a software interface having a plurality of procedures, a method for testing said software interface, said method comprising the steps of:a) providing corresponding test functions for each of said procedures; b) formally expressing a sequential execution order of said test functions, and specifying selected combinations of attribute values to be used with said designated order of executing said test functions, said selected combinations of attribute values being selectively assigned to attributes of said test function' parameter attributes when said test functions are invoked to test said procedures in order, said test functions comprising a plurality of parameters having a plurality of attributes; c) generating a test driver that executes said test functions in said expressed execution order with said selected combinations of said attribute values, said test driver calling user supplied test data creation and deletion functions to create and delete test data for each of said selected combinations of said attribute values; and d) providing said test data creation and deletion functions.
 13. The method as set forth in claim 12, wherein,said test functions are auto-checking test functions; and said test driver accumulates test statistics for said selected auto-checking test functions after executing each of said selected auto-checking test functions.
 14. In a computer system comprising a central processing unit (CPU) and a software interface having a plurality of procedures and corresponding test functions for testing said procedures, an apparatus for automatically generating a test driver for sequentially executing said test functions in order, said apparatus comprising:a) designating means comprising said CPU for receiving declaration of at least one local variable that is modified during testing of said procedures, said at least one local variable for facilitating passing of execution results form one test function to another test function evaluating a test expression, and designation formal expression of execution order of said test functions; b) specification means comprising said CPU for receiving specifications of assignable attribute values selected for each of said attributes of said test function' parameter attributes, said test functions comprising a plurality of parameters having a plurality of attributes, said attributes being assigned attribute values when said test functions are invoked; and c) generation means coupled to said designation and specification means comprising said CPU for generating said test driver based on said local variable declaration, said designated formal expression of execution order of test functions and said specified assignable attribute values, said generated test driver when invoked executes said designated test functions in accordance with said formally expressed order of execution, with all combinations of said specified assignable attribute values, using said at least one declared local variable.
 15. The apparatus as set forth in claim 14, wherein, said test functions are auto-checking test functions.
 16. The apparatus as set forth in claim 14, wherein,said formal test expressions include local test variable declarations; and said designation and specification means are also for receiving supplemental test function definitions to augment some of said test function designations and attribute value specifications.
 17. The apparatus as set forth in claim 14, wherein, said software interface is object oriented, and said designation and specification means are also for receiving supplemental object type and method definitions to augment some of said test function designations and attribute value specifications.
 18. The method as set forth in claim 14, wherein, said generation means is also for generating an include file for said generated test driver, said include file comprising attribute definitions and user supplied test data creation and deletion function definitions, said include file being included at compilation of said generated test driver.
 19. The apparatus as set forth in claim 14, wherein, said generation means is also for generating test driver functions for said generated test driver, said test driver functions being called by said generated test driver during its execution to provide said generated test driver with a particular combination of said attribute values.
 20. The apparatus as set forth in claim 14, wherein, said generation means comprises:c.1) parsing means coupled to said designation and specification means comprising said CPU for parsing and tokenizing elements of said test expression and said attribute value specifications based on a formal grammar; c.2) intermediate representation generation means coupled to said parsing means comprising said CPU for generating intermediate representations for said test expression and said attribute value specifications, said intermediate representation being a syntax tree; and c.3) code generation means coupled to said intermediate representation generation means comprising said CPU for generating executable code for said test driver using said generated intermediate representations. 